Concrete Calculator
Cubic yards and bags for slabs, footings and posts.
Enter your values
Results update instantly as you type — no submit needed.
Results
- Concrete needed
- 2.72 cubic yards
- Cubic feet
- 73.3
- 80 lb bags
- 123
- 60 lb bags
- 163
- Approximate weight
- 11,000 lb
Quick answer
Concrete volume is length × width × thickness converted to cubic yards; one 80 lb bag yields 0.6 cubic feet.
Cubic yards = L × W × T(ft) ÷ 27
How to use the Concrete Calculator
- 1Measure the length and width of the pour.
- 2Enter thickness in inches.
- 3Read cubic yards and bag counts.
Frequently asked questions
When should I order ready-mix?
Above about one cubic yard. Mixing 45 bags by hand is slow enough that cold joints form between batches.
How thick should a slab be?
4 inches for patios and walkways, 5–6 inches with rebar for driveways carrying vehicles.